A thermal cycler for implementing chemical and/or biological reactions comprising a body for accommodating one or more samples and a cover is disclosed, for example, in U.S. Pat. No. 5,475,610. According to one embodiment described therein, once the lid is closed, a torque knob is used to move a platen from a position of no contact with the reaction tubes into a position of contact and to apply a defined pressure onto capped tubes in a reaction block. Therein, it is essential that the caps on the tubes are resiliently deformable. A similar device is disclosed in U.S. Pat. No. 6,703,236. A similar set-up is disclosed in EP 1 013 342. In order to apply a pressure onto the reaction vessels containing a sample, an electrical positioner is actuated so that a movable part of the rigid cover is pressed against the caps of the reaction vessels.
WO 2006/002226 relates to a system for thermal cycling of samples. The system comprises a thermal cycling device having a plurality of cavities adapted to receive at least a portion of a plurality of sample wells and a heated lid. The system of WO '226 further comprises at least one pneumatic driver connected to the heated lid. The pneumatic driver is configured to position the heated lid in a closed position and an open position, and to move the heated lid between the closed position and the open position. The system also comprises at least one pneumatic actuator connected to the pneumatic driver. The pneumatic actuator is configured to actuate the pneumatic driver to automatically position and move the heated lid between the closed position and the open position.
The set-up according to these and similar prior art documents is not well suited to accommodate samples and/or reaction vessels or plates or blocks of different type and/or of different heights (or height tolerances) that are to be used in the same device in subsequent (different) experiments. The travel and the tolerances of the pneumatic drivers or actuators of the prior art are adapted to seal off a specific sample array with reaction vessels of a specific, fixed type and height. Specifically, the travel of the actuator may not be long enough to accommodate and properly seal a reaction vessel of small height and the pressure as exerted by closing the cover may be too high to accommodate a reaction vessel of a large height. In essence, the closing mechanisms of the prior art are not independent of the height of the reaction vessel or the (sample) plate or the (flat) block used to contain a sample or an array of samples.
In view of the prior art in the field, it is an object of the present invention to provide a device and a method according to which various different samples, in particular samples contained in reaction vessels or plates or blocks of different height or of differing height tolerances, can be thermally processed in one and the same device in different experiments. In particular, the pressure as exerted onto the reaction vessels or plates or blocks by means of closing and/or adjusting the means for covering of the device should be as independent of the height of the reaction vessels or plates or blocks as possible.
It is a further object of the present invention to provide a device and a method according to which the at least one sample is covered by said means for covering in a manner so that pressure can be applied as evenly and homogeneously as possible and in a manner so that potential evaporation of the sample or components of the sample is avoided or minimized and/or that condensation of vaporizable fluids of said sample on said means for covering and/or on the caps/lids of reaction vessels (if reaction vessels are used) and/or on the top part of sample wells (if multi-well plates or blocks are used) is minimized or avoided.
Furthermore, it is a preferred object according to the present invention to provide a device and a method that minimize or avoid damage and/or deformation of reaction vessels or plates or blocks during the process of covering the same, in particular damage or deformation caused by applying a pressure onto the reaction vessels or plates or blocks that is too high, or otherwise unsuited for the vessel/plate or block.